Field of the Invention
The present invention relates to a sheet-conveying device that conveys sheets, an image-forming apparatus using the sheet-conveying device and an image-forming system that uses such a sheet-conveying device.
Description of Related Art
Device including a sheet-conveying mechanism in an image-forming apparatus, a sheet-stapling apparatus that stapling the sheets and the like contains any guide members constituting a sheet-conveying path. In an image-forming system composed of the image-forming apparatus and various kinds of sheet-processing apparatuses, the sheets on which the image is formed by the image-forming apparatus pass through a sheet-conveying path having any guide members up to their ejections.
When a surface of sheet on which the image is formed contacts any of the guide members, the sheet may be scratched, which is called as “image scratch”. Japanese Patent Application Publication No. 2011-191706 discloses a curved sheet-conveying path in which the guide members are curved. In this curved sheet-conveying path, the sheet often contacts any of the curved guide members so that such an image scratch may be easy to occur.
Although the image scratch mainly occurs by contacting an image-formed surface of the sheet with a guide surface of any of the guide members, the image-formed surface of the sheet is particularly easy to contact an inner guide member of the guide members. Accordingly, the image scratch is easy to occur on the curved sheet-conveying path, which causes print quality of an output printed sheet to be remarkably deteriorated.
A past curved sheet-conveying path has coped with the occurrence of this image scratch by a configuration such that a driven roller composed of low friction material such as resin is provided to the inner guide member. Further, such a technology that a plurality of driven rollers constitutes a guide in the curved sheet-conveying path has been proposed (for example, see Japanese Patent Application Publication No. 2005-077732).